It would appear that the Samsung Galaxy Note 3 got updated to Android 5.0 Lollipop in Vietnam, via OTA, judging by the screenshots posted on the web by the owner of the phablet. The info comes from Samsung-Viet and we’re pretty wary of this finding.
Why? Because no other Vietnamese tech blog has written anything about it, so it could be forged. It could all be a big mistake, especially since Samsung is only said to release such big updates for popular devices in early 2015. Meanwhile some Galaxy S5 users in regions of the globe have received their Lollipop updates as well. The Note 3 is a more isolated case, though, limited to a single user for now.
Samsung-Updates, a site that specializes in archiving all Samsung updates as they appear had the 5.0 update for the SM-N900U Note 3 model, only to take it down fast, for a reason yet unknown. This means that even if you have the same model, you can’t get the update just yet. I’m guessing that a custom ROM is your best bet till the real deal comes.